The present disclosure relates to a protection device that covers a needle tip after puncturing a target of puncture with a needle, and a medical device assembled body attached with this protection device.
In a syringe used for injecting a patient, one provided with a protection device (medical device assembled body) has been developed to prevent inadvertent puncture of a needle after puncturing.
For example, a protection device disclosed in JP 4981030 A includes an inner member (supporting body) having a needle; and an outer cylinder (sleeve) disposed outside the inner member and relatively movable with respect to the inner member. In this case, a flexible tab is provided at a predetermined position closer to a proximal end of the inner member. The flexible tab extends in a distal end direction, and a distal end of the flexible tab is formed with a protrusion (peg). The outer cylinder includes a guiding path (traveling path) having a U-shape, configured to receive the protrusion of the inner member; and an elastic member (step) protruded from a peripheral wall toward a lock position in the guiding path.
At the time of puncturing with the needle, this protection device advances the inner member with respect to the outer cylinder so as to expose the needle from a distal end. At this time, the protrusion disposed in the guiding path is displaced to a puncture position at a distal end of the guiding path. After puncturing, the outer cylinder is pushed in the distal end direction by an internal spring so that the outer cylinder covers the needle. Accordingly, the protrusion is displaced along the guiding path in a proximal end direction, passing over a narrowed portion of the guiding path including the elastic member, thereafter being disposed in the lock position on a side closer to the proximal end. Even when a force to re-expose the needle (the receding movement of the outer cylinder) is applied to this lock position, the protrusion is caught in the elastic member so that exposure of the needle is avoided.